Don't let the difficulty put you off. Yes it is difficult but it is very rewarding to progress in a language. I got a B at GCSE and a C at AS. As long as you are willing to put the work in, go for it!
As for what you study, I was with AQA and we did topics like TV, Cinema, Fashion, Marriage, Sport, Healthy Eating etc. At my college, we have 3 90 minute lessons a week and each one was structured. Lesson one would be learning vocab for the topic of the week as well as reviewing the last week's work. Lesson two was always to practice listening exercises from past papers on the topic of the week. Then lesson three was tests on vocab, the grammar point/tense of the week and practicing essay writing. Generally French (and all language) classes tend to be smaller than other classes and I really enjoyed the closely knit group of people - we all helped each other and it was great.